What you'll find is that OS is a good, quality engine, just as many other brands are. All glow engines operate in largely the same way. If you know how to run a two-stroke OS, you know how to run most any other two-stroke out there. A four-stroke isn't that much different, either. What you find with four-strokes is a very generalized set of assumptions: Saitos, OS, and Magnums are largely on par for power. Saitos tend to weigh less for a given size, which sometimes leads to vibration. OS engines have a very nice finish, but you tend to pay more for an otherwise comparable Magnum. OS and Saito are the top brands, where Magnums are a budget brand. In practice, there doesn't seem to be a clear winner in terms of reliability or power. OS have a reputation for better fuel economy. Thunder Tiger produces engines that I feel are on a quality level equal to OS. They tend to be comparable in terms of power and weight, though the TT91 is heavier and more powerful than its peers. YS is a bit of a different breed - - they're what I consider to be premium engines in terms of finish and power, but they're slightly heavier and have a unique fuel system.

Picking an engine can be an intuitive process, based on a person's own experiences. The broader your experiences, the better your base of knowledge for picking an engine will be. When you're early in your modeling career, try a lot of different engines and brands. Built that base of experience, and you'll have the tools to make great decisions in the future. Narrow the choices by displacement and price, and then start to look at the restrictions the model puts on you. What size prop can you realistically run on a Cherokee? Do most people need to add weight to the nose or the tail? What is the engine mounting like - - if it is restrictive in terms of where the tank is, that can lead to certain choices being better than others.

All of that aside, though, you'll find no modern four-strokes that are clunkers. Isn't that nice?